[gradsusr] lon lat to km

[Jeff Duda]

Use this code:

'reinit'
'open try2.ctl'
'set grads off'
'set mproj latlon'
'set mpdset hires'
'set gxout shaded'
'set grid on'
'set lon 100  101'
'set lat -1  0'
'define dx = *6.371e3**cos(-1*(3.14159/180))*cdiff(100,0)*(3.14159/180)'
'define dy = *6.371e3**cdiff(-1,0)*(3.14159/180))'
'define xdist = ((lon-100)/0.004492369)*(dx/2)'
'define ydist = ((lat-0)/0.004522556)*(dy/2)'
'set z 5'
'set t 1'
'd ref'

The square brackets were just to show different groupings.  When it comes
time to code it, you must use only parentheses.

The above should work.

Jeff

On Sat, Feb 2, 2013 at 1:41 AM, wendi harjupa <wendiharjupa at gmail.com>wrote:

> Dear Mr. Jeff
>
> Thank you very much for your explanation,
> but I am very sorry, I still do not get it,
>
> I made new script
>
> 'reinit'
> 'open try2.ctl'
> 'set grads off'
> 'set mproj latlon'
> 'set mpdset hires'
> 'set gxout shaded'
> 'set grid on'
> 'set lon 100  101'
> 'set lat -1  0'
> 'define dx = *6.371e3**cos(-1*(3.14159/180))*cdiff(100,0)*(3.14159/180)'
> 'define dy = *6.371e3**cdiff(-1,0)*(3.14159/180))'
> 'define xdist = ((lon-100)/0.004492369)*(dx/2]'
> 'define ydist = ((lat-0)/0.004522556)*dy/2]'
> 'set z 5'
> 'set t 1'
> 'd ref'
>
> I checked grads document and I found that 6.371e3 is radius of the earth
> (6371 to 6374 km)*.*
> *
> *
> *I tried to change "*6.371e3" to "0e10" which is mean 0 to 10 km)
> But still the program did not run normally.
>
> I changed the value of lon and lat in script with 100 and -1.
> but still I got error.
>
> Please help me to solve it.
>
> Thank you very much
> Best regards,
> wendi
>
> On Sat, Feb 2, 2013 at 2:21 AM, Jeff Duda <jeffduda319 at gmail.com> wrote:
>
>> Wendi,
>> You need to run those two define commands at the top of my previous email
>> before attempting to define the xdist and ydist fields.  Also, since I can
>> see your control file information, I can see that dlon is 0.004492369 and
>> dlat is  0.004522556.  So substitute those two values into your expressions
>> for xdist and ydist also.
>>
>> Jeff
>>
>>
>> On Fri, Feb 1, 2013 at 4:36 AM, wendi harjupa <wendiharjupa at gmail.com>wrote:
>>
>>> Dear Mr. Jeff
>>>
>>> I have tried to use the scipt which you suggested,
>>> But, still I could not do it. Would you help me more...
>>>
>>> here I send my gs file :
>>>
>>>  'reinit'
>>> 'open try2.ctl'
>>> 'set grads off'
>>> 'set mproj latlon'
>>> 'set mpdset hires'
>>> 'set gxout shaded'
>>> 'set grid on'
>>> 'set lon 100  101'
>>> 'set lat 0  1'
>>> 'define xdist = [(lon 99.7)/dlon]*[dx/2]'
>>> 'define ydist = [(lat -1.02)/dlat]*[dy/2]'
>>> 'set z 5'
>>> 'set t 1'
>>> 'd ref'
>>>
>>> Below is my ctl file :
>>>
>>> DSET 1013.dat
>>> TITLE  RADAR
>>> OPTIONS  TEMPLATE LITTLE_ENDIAN
>>> UNDEF  -1000
>>> XDEF    321 LINEAR    99.688120996    0.004492369
>>> YDEF    321 LINEAR    -1.083708891    0.004522556
>>> ZDEF    39  LINEAR   1.0 0.5
>>> TDEF    15 LINEAR 13:00Z10apr2004  4mn
>>> VARS    2
>>> ref 39  99  Reflectivity(dBZ)
>>> vel 39  99  Doppler Velocity(m/s)
>>> ENDVARS
>>>
>>>
>>> Would you check my gs file, is there something that I have to revise??
>>>
>>> Thank you very much.
>>>
>>> Best regards,
>>> wendi
>>>
>>>
>>>
>>> On Fri, Feb 1, 2013 at 10:34 AM, Jeff Duda <jeffduda319 at gmail.com>wrote:
>>>
>>>> These commands will help.
>>>>
>>>> 'define dx = 6.371e3*cos(lat*(3.14159/180))*cdiff(lon,x)*(3.14159/180)'
>>>> 'define dy = 6.371e3*cdiff(lat,y)*(3.14159/180))'
>>>>
>>>> They define grid increments in terms of spatial distance rather than
>>>> geographic distance.  If you're trying to change the axes and tick marks,
>>>> you'll have to define an origin and define your x and y distances based on
>>>> that.  For instance, if you set your lower left domain corner (latitude 0
>>>> and longitude 100), then you can define your coordinate distances using
>>>>
>>>> 'define xdist = [(lon-100)/dlon]*[dx/2]'
>>>> 'define ydist = [(lat-0)/dlat]*[dy/2]'
>>>>
>>>> I think this should work, but I haven't tested it myself, so I don't
>>>> know.  dlon and dlat are the step values from the XDEF and YDEF lines of
>>>> the control file, respectively.
>>>>
>>>> Jeff Duda
>>>>
>>>> On Thu, Jan 31, 2013 at 7:02 AM, wendi harjupa <wendiharjupa at gmail.com>wrote:
>>>>
>>>>> Dear Sir/Madam
>>>>>
>>>>> I need help
>>>>> I have problem with grads command,
>>>>> I am not well understand with command gr2XY,
>>>>>
>>>>> Actually I want to convert the lon 100  to 101, and lat 0 to 1 to
>>>>> distance (km)
>>>>> let think that lon 100 is 0 km, and lat 0 is 0 km,
>>>>>
>>>>> what command I can use to convert lon and lat to km?
>>>>>
>>>>> Thank you very much for your help
>>>>>
>>>>> best regards,
>>>>> --
>>>>> -------------
>>>>> Wendi Harjupa. ST
>>>>> Shimane University Graduate School of Engineering Sciences
>>>>> Department of Electronic Control Systems
>>>>> Remote Sensing Laboratory
>>>>> s119447
>>>>> Cellphone : +81-080-4268-6676
>>>>> email : wendi at rslab.riko.shimane-u.ac.jp
>>>>>
>>>>> _______________________________________________
>>>>> gradsusr mailing list
>>>>> gradsusr at gradsusr.org
>>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Jeff Duda
>>>> Graduate research assistant
>>>> University of Oklahoma School of Meteorology
>>>> Center for Analysis and Prediction of Storms
>>>>
>>>> _______________________________________________
>>>> gradsusr mailing list
>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
>>>
>>>
>>> --
>>> -------------
>>> Wendi Harjupa. ST
>>> Shimane University Graduate School of Engineering Sciences
>>> Department of Electronic Control Systems
>>> Remote Sensing Laboratory
>>> s119447
>>> Cellphone : +81-080-4268-6676
>>> email : wendi at rslab.riko.shimane-u.ac.jp
>>>
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>
>>>
>>
>>
>> --
>> Jeff Duda
>> Graduate research assistant
>> University of Oklahoma School of Meteorology
>> Center for Analysis and Prediction of Storms
>>
>> _______________________________________________
>> gradsusr mailing list
>> gradsusr at gradsusr.org
>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>
>
> --
> -------------
> Wendi Harjupa. ST
> Shimane University Graduate School of Engineering Sciences
> Department of Electronic Control Systems
> Remote Sensing Laboratory
> s119447
> Cellphone : +81-080-4268-6676
> email : wendi at rslab.riko.shimane-u.ac.jp
>
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr
>
>


-- 
Jeff Duda
Graduate research assistant
University of Oklahoma School of Meteorology
Center for Analysis and Prediction of Storms
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://gradsusr.org/pipermail/gradsusr/attachments/20130202/f87ef6d0/attachment-0003.html